JP4930213B2 - Automatic transmission abnormality diagnosis device and automatic transmission control system - Google Patents

Description

  The present invention provides a friction element that is used for switching a plurality of power transmission paths and that is switched between an engaged state and a released state by a working fluid, and the pressure of the working fluid that acts on the friction element is With respect to an automatic transmission including a pressure response member that is in a different state between a value when the friction element is brought into an engaged state and a value when the friction element is brought into a released state, a gear ratio is controlled by an operation of the state of the friction element. In connection with this, the present invention relates to an abnormality diagnosis device for an automatic transmission for diagnosing the presence or absence of abnormality in the control of the gear ratio based on the state of the pressure response member. The present invention also relates to an automatic transmission control system equipped with the abnormality diagnosis device.

  In the automatic transmission, a plurality of clutches and brakes (friction elements) are engaged or disengaged with hydraulic oil, so that the power transmission path constituted by the planetary gear mechanism is switched. In recent years, so-called linear motion control that individually and electronically controls the pressure of the hydraulic oil acting on each friction element, for the purpose of simplifying the hydraulic control circuit for controlling the pressure of the hydraulic oil and improving the pressure control performance, etc. Automatic transmissions equipped with devices have also been put into practical use.

  As an abnormality diagnosis device for the automatic transmission, for example, as shown in Patent Document 1 below, a pressure switch that can take two states of on and off according to the pressure of hydraulic oil acting on each friction element is used. It has also been proposed to diagnose whether there is an abnormality in the control of the gear ratio. Specifically, based on the combination of the states of the pressure switch, it is determined whether or not an abnormal engagement pattern of the friction elements has occurred.

However, in this case, when the gear ratio is switched, there may occur a situation in which the state of the pressure switch is different from the state assumed from the gear ratio after switching even though the control is normal. Especially when the hydraulic oil is at low temperature, the change in the hydraulic oil pressure becomes dull. Therefore, when changing the gear ratio, the state of the pressure switch should correspond to the abnormal engagement pattern of the friction elements. There is. In order to avoid erroneous diagnosis in such a situation, in Patent Document 2 below, the diagnosis of the presence or absence of abnormality is stopped during the gear ratio switching control.
Japanese Patent No. 3424159 Japanese Patent No. 3695257

  By the way, the abnormalities in the steady state in which the gear ratio of the automatic transmission is fixed are substantially limited to an electrical failure such as a sudden disconnection of a signal line. An electrical failure can be detected by the control device. On the other hand, during the gear ratio switching control, the pressure applied to the friction element cannot be increased despite the desire to increase the pressure, or cannot be decreased regardless of the desire to decrease the pressure. There is a risk of abnormalities such as In this case, when the abnormality diagnosis is stopped during the gear ratio switching control as in the above-described diagnosis device, the diagnosis of the abnormality is delayed.

  The present invention has been made in order to solve the above-mentioned problems, and its object is to control the abnormality of the control of the speed ratio based on the state of the pressure response member when the speed ratio is controlled by the operation of the state of the friction element. An object of the present invention is to provide an abnormality diagnosis device and an abnormality diagnosis system for an automatic transmission capable of diagnosing the presence / absence more quickly and with high accuracy.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

The invention according to claim 1 is a friction element that is used for switching a plurality of power transmission paths and that is switched between an engaged state and a released state by a working fluid, and the working fluid that acts on the friction element. An automatic transmission including a pressure response member that is in a state different between a value when the friction element is brought into an engaged state and a value when the friction element is brought into a released state. In the automatic transmission abnormality diagnosis device for diagnosing whether or not the transmission ratio control is abnormal based on the state of the pressure response member, the state of the pressure response member corresponds to the control of the transmission ratio. Estimating means for estimating a period that does not correspond to the operating state of the friction element based on a command value of the pressure of the working fluid; and And a prohibiting means for prohibiting the judgment to the effect that there is an abnormality in the pressure responsive member includes a first pressure threshold is the engagement of transitions from state corresponding to the released state to a state corresponding to the engagement Is set to be larger than a second pressure threshold value at the time of transition from the state corresponding to the combined state to the state corresponding to the released state, and when the engaged state is set, the command value of the pressure of the working fluid is set. After once increasing to a value larger than the first pressure threshold, performing a quick filling process of lowering the first pressure threshold, and after the quick filling process, performing a process of gradually increasing the command value, In the estimation, the estimating means assumes that the pressure response member is in a state corresponding to the engaged state when the pressure of the working fluid is equal to or higher than the first pressure threshold, and the pressure of the working fluid. Is the second When the pressure response member is equal to or less than the force threshold, the pressure response member is in a state corresponding to the released state, and the end of the period that does not correspond is estimated based on the command value when the gradually increasing process is performed It is characterized by doing.

When the engagement and release operations are performed by applying the pressure of the working fluid to the friction element, a command value for the pressure of the working fluid is set. When the pressure command value is set, the actual pressure is controlled in accordance with the pressure command value. Therefore, the actual pressure has a correlation with the pressure command value. On the other hand, a pressure response member will be in a different state according to a pressure. For this reason, the command value of pressure and the state of the pressure response member have a correlation, and the state of the pressure response member can be estimated based on the command value of pressure. Then, it is prohibited to determine that there is an abnormality in the speed ratio control in a period in which the estimated state does not correspond to the operation state of the friction element according to the speed ratio control. Accordingly, it is possible to avoid determining that there is an abnormality when the diagnosis of the presence or absence of the abnormality cannot be appropriately performed depending on the state of the pressure response member. In addition, by canceling the prohibition outside the above period, it is possible to diagnose the presence or absence of abnormality as quickly as possible.
In particular, in the above invention, by focusing on the two threshold values of the pressure response member having hysteresis, the state of the pressure response member can be suitably estimated based on the pressure command value.

  According to a second aspect of the present invention, in the first aspect of the present invention, the estimating means is configured to change the friction element from one of the released state and the engaged state to the other according to the change in the transmission gear ratio. The time period during which the state of the pressure response member shifts to the one corresponding to the other state is estimated based on the command value of the pressure of the working fluid that acts on the friction element.

  When changing the gear ratio, when the friction element changes from one of the released state and the engaged state to the other, an abnormality may occur in which the pressure of the fluid acting on the friction element does not become a desired state. In this case, since the gear ratio cannot be changed to a desired value, it is particularly desirable to quickly grasp the abnormality. On the other hand, when the speed ratio is changed, the state of the pressure response member becomes a transitional state, so that there is a possibility that it may be erroneously determined that the speed ratio is abnormal although the speed ratio control is normal. In this regard, in the above invention, by providing the prohibiting means, it is possible to quickly diagnose the presence or absence of an abnormality when it becomes possible to diagnose the presence or absence of an abnormality according to the state of the pressure response member.

  According to a third aspect of the present invention, in the first or second aspect of the invention, when the estimation means estimates the period based on the command value, a response of an actual pressure of the working fluid to a change in the command value It is characterized by adding a delay time.

  A response delay occurs in the actual pressure change with respect to the change in the command value of the working fluid pressure. For this reason, when the gear ratio is changed, the time required for the state of the pressure response member to be in a state corresponding to the operation state of the friction element is affected by an actual pressure response delay. In the above invention, in view of this point, the period can be estimated with higher accuracy by taking the response delay time into account.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the estimating means grasps the response delay time based on a temperature of the working fluid .

  The actual pressure response to the command value of the working fluid pressure depends on the temperature of the working fluid. Specifically, the responsiveness decreases as the temperature of the working fluid decreases. For this reason, when the speed ratio is changed, the time required for the state of the pressure response member to become the state corresponding to the operation state of the friction element depends on the temperature of the working fluid. In this regard, in the above invention, when estimating the period in which the state of the pressure response member does not correspond to the operating state of the friction element, the responsiveness of the working fluid is estimated in the estimation of the period by taking the temperature of the working fluid into consideration. The temperature dependence can be taken into account, and as a result, the period can be estimated with higher accuracy.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the state of the pressure response member and the operation state of the friction element are in a predetermined period in a state where the determination prohibition by the prohibiting unit is released. It is characterized by comprising a judging means for judging that the control is abnormal based on the fact that it no longer responds.

  In the above invention, it is determined that there is an abnormality based on the fact that the period in which the state of the pressure response member does not correspond to the operation state of the friction element continues for a predetermined period or longer, so that it is extremely short due to the influence of noise or the like. It is possible to avoid making an erroneous determination that there is an abnormality in the case where the state does not correspond to the above during the period. For this reason, the diagnosis that there is an abnormality can be performed with higher accuracy.

The invention according to claim 6 is the invention according to any one of claims 1 to 5 , wherein the second pressure threshold value is set to a value lower than a minimum value at which a force for engaging the friction element is generated. It is characterized by becoming.

  According to the above setting, two different states of the pressure response member can be appropriately associated with two different states of the friction element.

The invention according to claim 7 is an automatic transmission control system comprising the abnormality diagnosis device for an automatic transmission according to any one of claims 1 to 6 and the automatic transmission.

  Hereinafter, an embodiment in which an automatic transmission abnormality diagnosis device and an automatic transmission control system according to the present invention are applied to an in-vehicle automatic transmission control system will be described with reference to the drawings.

  FIG. 1 shows the configuration of the automatic transmission control system.

  As shown in the figure, an output shaft 11 of the engine 10 is connected to an input shaft 13 of a torque converter 12. Inside the torque converter 12, a pump impeller 14 and a turbine runner 15 constituting a fluid coupling are provided to face each other, and a stator 16 that rectifies the flow of oil is provided between the pump impeller 14 and the turbine runner 15. Is provided. The pump impeller 14 is connected to the input shaft 13 of the torque converter 12, and the turbine runner 15 is connected to the output shaft 17 of the torque converter 12. The torque converter 12 is provided with a lockup clutch 18 for engaging or disengaging between the input shaft 13 side and the output shaft 17 side.

  The output shaft 17 of the torque converter 12 is connected to the input shaft 22 of the transmission gear mechanism 20. The transmission gear mechanism 20 includes a plurality of gears and a friction element for forming a plurality of transmission paths by the gears. Specifically, planetary gear mechanisms 24 to 28 are provided as the gears. In addition, a plurality of clutches C0, C1, C2, brakes B0, B1, B2, B3 and a plurality of one-way clutches F0, F1, F2 are provided as friction elements.

  The torque of the engine 10 is taken into the input shaft 22 of the transmission gear mechanism 20 via the torque converter 12, and is shifted to a predetermined speed by the transmission gear mechanism 20 and output from the output shaft 30. And the torque output from the output shaft 30 is transmitted to the drive wheel of a vehicle.

  The transmission gear mechanism 20 is provided with a hydraulic pump (not shown) driven by the power of the engine 10, and a hydraulic control circuit 40 is provided in an oil pan (not shown) that stores hydraulic oil (oil). Is provided. The hydraulic control circuit 40 includes a line pressure control circuit 42, an automatic transmission control circuit 44, a lockup control circuit 46, and a manual switching valve 48.

  Here, the hydraulic oil pumped up by a hydraulic pump from an oil pan (not shown) is supplied to the automatic transmission control circuit 44 and the lockup control circuit 46 via the line pressure control circuit 42. The line pressure control circuit 42 is provided with a hydraulic control valve (not shown) for line pressure control that controls the hydraulic pressure from the hydraulic pump to a predetermined line pressure. The automatic transmission control circuit 44 includes a plurality of transmission hydraulic control valves (not shown) for controlling the hydraulic pressure supplied to the clutches C0, C1, C2 and the brakes B0, B1, B2, B3 of the transmission gear mechanism 20. Is provided. The lockup control circuit 46 is provided with a lockup control hydraulic control valve (not shown) for controlling the hydraulic pressure supplied to the lockup clutch 18.

  The manual switching valve 48 is a valve body that is provided between the line pressure control circuit 42 and the automatic transmission control circuit 44 and is switched in conjunction with the operation of the shift lever 50. The manual switching valve 48 is for manually switching the gear position by operating the shift lever 50 even when the power supply to the hydraulic control valve of the automatic transmission control circuit 44 is stopped. That is, even if the shift lever 50 is operated to the neutral range (N range) or the parking range (P range) and the power supply to the hydraulic control valve of the automatic transmission control circuit 44 is stopped (OFF), The switching valve 48 switches the hydraulic pressure supplied to the transmission gear mechanism 20 so that the transmission gear mechanism 20 is in a neutral state.

  FIG. 2 shows the configuration of the automatic transmission control circuit 44.

  As shown in the figure, the automatic transmission control circuit 44 applies the hydraulic pressure applied to the friction element from the pressure source for each of the hydraulically driven friction elements (clutch C0, C1, C2, brake B0, B1, B2, B3). A hydraulic control valve 52 for adjusting each is provided. FIG. 3 illustrates a friction element that is hydraulically driven by the hydraulic control valve 52. Specifically, FIG. 3A shows the released state of the friction element, and FIG. 3B shows the engaged state of the friction element.

  As shown in the drawing, each friction element includes a friction plate FB connected to the planetary gear side and a metal plate MB. Each friction element includes a piston P. A force is exerted on the piston P by a return spring RS in a direction in which the friction element is released (a direction in which the friction plate FB and the metal plate MB are separated from each other). Further, the pressure of the hydraulic oil controlled by the hydraulic control valve 52 can be applied to the piston P in the direction in which the friction element is engaged.

  The automatic transmission control circuit 44 shown in FIG. 2 is further provided with a pressure switch 60 that takes a binary state of an on state and an off state according to the pressure acting on each friction element. Yes.

  FIG. 4 shows the structure of the pressure switch 60. Specifically, FIG. 4A shows an off state of the pressure switch 60, and FIG. 4B shows an on state of the pressure switch 60.

  As shown in the drawing, the body 61 of the pressure switch 60 is provided with an oil passage 62 that communicates with the hydraulic control valve 52 and a hydraulic path between the friction elements. The oil passage 62 is provided with a conductive diaphragm 63 made of, for example, a disc spring. A power supply side terminal 64 is provided on the opposite side of the diaphragm 63 from the oil passage 62. Here, the power supply side terminal 64 is connected to a positive electrode terminal of a power supply (not shown). On the other hand, the diaphragm 63 is connected to the output terminal of the pressure switch 60.

  In such a configuration, when the pressure in the oil passage 62 is low as shown in FIG. 4A, the diaphragm 63 is separated from the power supply side terminal 64, so that the pressure switch 60 is turned off. On the other hand, as shown in FIG. 4B, when the pressure in the oil passage 62 becomes higher than a predetermined level, the diaphragm 63 is deformed, so that the diaphragm 63 and the power supply side terminal 64 come into contact with each other. As a result, the pressure switch 60 is turned on.

  As shown in FIG. 5, the pressure switch 60 has hysteresis, and the pressure threshold value α when changing from the off state to the on state is the pressure threshold value when changing from the on state to the off state. It is larger than β. The pressure threshold value β when changing from the on state to the off state is set to be lower than the minimum value of the value at which the hydraulic pressure acting on the friction element compresses the return spring RS and generates the engagement force.

  On the other hand, the output shaft 11 of the engine 10 shown in FIG. 1 is provided with a crank angle sensor 70 for detecting the rotation angle. Further, the input shaft 22 of the transmission gear mechanism 20 is provided with an input side rotation sensor 72 that detects its rotation angle, and the output shaft 30 of the transmission gear mechanism 20 has an output side rotation that detects its rotation angle. A sensor 74 is provided. The shift lever 50 is provided with a shift position sensor 76 for detecting the operation position.

  The output signal of the oil temperature sensor 78 that detects the temperature of the hydraulic oil, the output signal of the throttle sensor 80 that detects the opening degree of the throttle valve of the engine 10, the vehicle speed sensor that detects the speed of the vehicle. The output signal 82 is input to an electronic control unit (ECU 90) for an automatic transmission. The ECU 90 controls the gear ratio based on the input signal and the like. That is, for example, according to a shift speed change request (target shift speed change request) generated according to the operation position of the shift lever 50 and the operating conditions of the engine 10 (throttle opening, vehicle speed, etc.), according to a preset shift pattern. An energization operation is performed on each hydraulic control valve 52 of the automatic transmission control circuit 44 so that the transmission gear mechanism 20 is shifted. As a result, the hydraulic pressure applied to each clutch C0, C1, C2 and each brake B0, B1, B2, B3 of the transmission gear mechanism 20 is controlled, and each clutch C0, C1, C2 and each brake B0, B1, B2, B3 is controlled. Is engaged / released. Thereby, the gear ratio of the transmission gear mechanism 20 is switched by switching the combination of the gears of the planetary gear mechanisms 24 to 28 that transmit power.

  FIG. 6 shows combinations of engagements of the clutches C0, C1, C2 and brakes B0, B1, B2, B3 in the transmission gear mechanism 20 according to the present embodiment. In FIG. 6, the circles indicate the clutches and brakes that are held in the engaged state (torque transmission state) at the shift speed, and the unmarked state indicates the released state. When these engagement / release are switched by hydraulic pressure, the gear combinations of the planetary gear mechanisms 24 to 28 are switched, and the gear ratio is switched. For example, when downshifting from the 3rd speed to the 2nd speed, the clutch C1 held in the engaged state at the 3rd speed is released, and instead, the brake B2 is engaged, so that the downshift is performed to the 2nd speed. The Further, when upshifting from the 3rd speed to the 4th speed, the brake B1 held in the engaged state at the 3rd speed is released, and instead, the clutch C0 is engaged and the upshift is performed to the 4th speed. The

  By the way, when a malfunction occurs in the hydraulic control valve 52 due to foreign matters mixed into the hydraulic control valve 52 when the speed ratio is switched, the state of the friction element may be different from that shown in FIG. . In particular, depending on the abnormal engagement state of the friction element, there is a possibility that the interlock state where the rotation of the output shaft 30 stops is brought about. Therefore, in the present embodiment, the presence / absence of abnormality in the control of the gear ratio is diagnosed based on the state of the pressure switch 60. In particular, in the present embodiment, in order to perform this diagnosis as early as possible after the gear ratio is switched, a period during which the diagnosis can be performed is estimated based on the hydraulic pressure command value.

  FIG. 7 shows an abnormality diagnosis mode according to this embodiment. Specifically, FIG. 7 (a) shows the behavior of the engagement side hydraulic pressure, and FIG. 7 (b) shows the behavior of the release side hydraulic pressure.

  As shown in FIG. 7 (a), when engaging the friction element, the hydraulic pressure command value indicated by the one-dot chain line in the figure is once greatly increased to rapidly fill the friction element with hydraulic oil. Process. When the quick filling process is completed, the command value is decreased and then the command value is gradually increased, so that the command value of the hydraulic pressure is increased in a mode suitable for the change of the gear ratio. In the figure, the solid line indicates the actual hydraulic pressure behavior at this time. As shown in the figure, the actual hydraulic pressure follows the command value except for the rapid filling period. For this reason, the actual hydraulic pressure can be estimated based on the command value. In particular, in the present embodiment, the timing at which the pressure switch 60 is turned on when the actual hydraulic pressure reaches the pressure threshold value α is estimated based on the command value. When the hydraulic pressure acting on the friction element that shifts to the engaged state by switching the gear ratio is equal to or higher than the pressure threshold value α, it is assumed that the pressure switch 60 is on. For this reason, when the actual pressure switch 60 is not in the ON state at this time, there is an abnormality in the actual hydraulic oil pressure, and the friction element may not shift to the engaged state. . In this embodiment, paying attention to this point, the presence / absence of abnormality in the control of the gear ratio is diagnosed based on the state of the pressure switch 60 when the pressure threshold value α is greater than or equal to.

  On the other hand, as shown in FIG. 7B, when releasing the friction element, a process of reducing the hydraulic pressure command value indicated by the one-dot chain line in the drawing in an appropriate manner for switching the gear ratio is performed. . At this time, the actual hydraulic pressure indicated by the solid line in the drawing follows the command value. Therefore, based on the command value, it is possible to estimate the timing at which the actual hydraulic pressure becomes equal to or lower than the pressure threshold β, that is, the timing at which the pressure switch 60 shifts to the off state. When the hydraulic pressure acting on the friction element that shifts to the released state by switching the gear ratio is equal to or lower than the pressure threshold β, it is assumed that the pressure switch 60 is off. For this reason, when the actual state of the pressure switch 60 at this time is not in the OFF state, it is considered that the actual hydraulic oil pressure is abnormal and the friction element may not shift to the released state. In the present embodiment, paying attention to this point, the presence or absence of an abnormality in the control of the gear ratio is diagnosed based on the state of the pressure switch 60 when the pressure threshold value β is below the threshold value β.

  The above estimation is performed in consideration of the actual oil pressure follow-up delay with respect to the command value. That is, as illustrated on the release side in FIG. 8, the timing at which the actual hydraulic pressure decreases to the pressure threshold β is delayed with respect to the timing at which the command value illustrated by the one-dot chain line decreases to the pressure threshold β. Therefore, by estimating the delay time (delay TD), the timing at which the actual oil pressure becomes a value that changes the state of the pressure switch 60 is estimated.

  FIG. 9 shows the procedure of the engagement-side abnormality determination prohibition process according to this embodiment. This process is repeatedly executed by the ECU 90, for example, at a predetermined cycle.

  In this series of processes, first, in step S10, it is determined whether or not the shift control is started. This process is to determine whether or not the gear ratio switching request is generated in the ECU 90 according to the operating state of the engine 10 and the switching is executed. If it is determined that the shift control is started, in step S12, an engagement-side prohibition flag that prohibits abnormality diagnosis for the friction element that shifts from the released state to the engaged state by switching the gear ratio. Turn on. When the process of step S12 is completed, the process waits until the quick filling process period for temporarily increasing the command value to rapidly fill the friction element with the hydraulic oil is completed (step S14).

  When the rapid filling process period is completed, the process waits until the hydraulic pressure command value reaches the pressure threshold value α (step S16). When it is determined that the pressure has risen to the pressure threshold value α, in step S18, the estimated time required for the actual hydraulic pressure to drop to the pressure threshold value α after the command value has dropped to the pressure threshold value α is counted. Increment the counter. In the subsequent step S20, based on the temperature of the hydraulic oil detected by the oil temperature sensor 78, the time required for the actual oil pressure to decrease to the pressure threshold value α after the command value has decreased to the pressure threshold value α is described above. The delay TD is calculated. Here, the temperature of the hydraulic oil is used because the temperature of the hydraulic oil is a parameter that changes the viscosity of the hydraulic oil, and thus the actual pressure response of the hydraulic oil can change depending on the temperature of the hydraulic oil. Specifically, as shown in FIG. 10, the delay TD is calculated using a map that defines the relationship between the temperature of the hydraulic oil and the delay TD. As shown in the figure, the delay TD is longer as the temperature of the hydraulic oil is lower. This is because the lower the operating oil temperature, the higher the operating viscosity, and the lower the operating oil temperature, the lower the response.

  In a succeeding step S22, it is determined whether or not the counter value is equal to or greater than the delay TD. This process determines whether or not the actual hydraulic pressure has decreased to the pressure threshold value α. If the counter value is less than the delay TD, the process returns to step S18. On the other hand, if the counter value is equal to or greater than the delay TD, the engagement side prohibition flag is turned off and the counter is initialized in step S24.

  FIG. 11 shows the procedure of the release side abnormality determination prohibition process according to the present embodiment. This process is repeatedly executed by the ECU 90, for example, at a predetermined cycle.

  In this series of processes, first, in step S30, it is determined whether or not the shift control is started, as in step S10 of FIG. If it is determined that the shift control has been started, a release-side prohibition flag that prohibits abnormality diagnosis for the friction element that shifts from the engaged state to the released state by switching the gear ratio is set in step S32. Turn on. When the process of step S32 is completed, the process waits until the hydraulic pressure command value becomes equal to or less than the pressure threshold value β (step S34). Then, if it is determined that the pressure has decreased below the pressure threshold β, in step S36, the estimated time required from the time when the command value decreases to the pressure threshold β to the time when the actual hydraulic pressure decreases to the pressure threshold β. Increment the counter to count. In the subsequent step S38, the actual hydraulic pressure is reduced to the pressure threshold value β after the command value has decreased to the pressure threshold value β based on the temperature of the hydraulic oil detected by the oil temperature sensor 78 in the manner of step S20 in FIG. The above-described delay TD, which is the time required for the time to decrease to the above, is calculated.

  In the subsequent step S40, it is determined whether or not the counter value is equal to or greater than the delay TD. This process is provided for the same purpose as step S22 in FIG. If the counter value is less than the delay TD, the process returns to step S36. On the other hand, if the counter value is equal to or greater than the delay TD, the release side prohibition flag is turned off and the counter is initialized in step S42.

  FIG. 12 shows the procedure of the diagnosis process for the presence or absence of abnormality in the control of the gear ratio according to this embodiment. This process is repeatedly executed by the ECU 90, for example, at a predetermined cycle. This process is performed for each friction element, but in the following description, the engagement side friction element is taken as an example.

  In this series of processing, first, in step S50, it is determined whether or not the engagement side prohibition flag is off. If the engagement side prohibition flag is off, the process proceeds to step S52 in order to diagnose whether there is an abnormality. In step S52, the output of the pressure switch 60 corresponding to the corresponding engagement-side friction element (clutch or brake) is detected.

  In a succeeding step S54, it is determined whether or not the output of the pressure switch 60 is normal. This process can be performed depending on whether or not the state of the pressure switch 60 corresponds to the operation state of the friction element according to the control of the transmission ratio. And when not respond | corresponding, it transfers to step S56 noting that the output of the pressure switch 60 is abnormal. In step S56, an abnormality determination counter that counts the continuous number of times that the output of the pressure switch 60 is determined to be abnormal is incremented. In a succeeding step S58, it is determined whether or not the abnormality determination counter is equal to or greater than a threshold value γ. This process is for determining whether or not the abnormality of the output of the pressure switch 60 is the abnormality of the control of the gear ratio. That is, when noise is mixed in the output of the pressure switch 60, it is determined that the output of the pressure switch 60 is abnormal although there is no abnormality in the speed ratio control. Whether or not the ratio control is abnormal is identified. The threshold γ is set to a value that is difficult to assume as an abnormal output continuation period due to noise mixed in the output of the pressure switch 60.

  If it is determined that the value is greater than or equal to the threshold value γ, it is determined in step S60 that the shift control is abnormal. On the other hand, if it is determined in step S54 that the output of the pressure switch 60 is normal, an abnormality determination counter is initialized in step S62.

  In addition, when the process of said step S60, S62 is completed, or when negative determination is made in step S50, S58, this series of processes is once complete | finished.

  As described above, in the present embodiment, it is determined that there is an abnormality in the control during the period in which it is estimated that the state of the pressure switch 60 does not correspond to the operation state of the friction element according to the control of the gear ratio based on the hydraulic pressure command value. By prohibiting, it is possible to avoid an erroneous determination that there is an abnormality. In addition, when the gear ratio switching control is performed, if the state of the pressure switch 60 is estimated to correspond to the operation state of the friction element corresponding to the gear ratio control based on the hydraulic pressure command value, the prohibition of abnormality diagnosis is released immediately. In addition, after the start of the gear ratio switching control, it is possible to quickly diagnose whether there is an abnormality in the gear ratio.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) A period in which the state of the pressure switch 60 does not correspond to the operating state of the friction element according to the control of the gear ratio is estimated based on the command value of the hydraulic oil pressure, and in a period in which it does not correspond, The judgment that there is an abnormality in the control was prohibited. Thereby, the presence or absence of abnormality can be diagnosed as quickly as possible while avoiding an erroneous determination that there is an abnormality.

  (2) When the friction element changes from one of the released state and the engaged state to the other in accordance with the change in the gear ratio, the pressure switch 60 is based on the command value of the hydraulic oil pressure acting on the friction element. The period during which the state changes to the one corresponding to the other state was estimated. This makes it possible to quickly diagnose the presence / absence of an abnormality when it is possible to diagnose the presence / absence of an abnormality according to the state of the pressure switch 60 in a situation where it is particularly desirable to quickly grasp an abnormality in the gear ratio. it can.

  (3) When estimating the period when the state of the pressure switch 60 does not correspond to the operation state of the friction element according to the gear ratio based on the command value of the hydraulic oil, the temperature of the hydraulic oil is taken into account. Thereby, the above estimation can be performed with higher accuracy.

  (4) Based on the fact that the state of the pressure switch 60 does not correspond to the operation state of the friction element for a predetermined period or longer, it is determined that the transmission ratio control is abnormal. As a result, it is possible to avoid making an erroneous determination that there is an abnormality in the case where the above-mentioned state does not correspond for a very short time due to the influence of noise or the like. For this reason, the diagnosis that there is an abnormality can be performed with higher accuracy.

  (5) Pressure when the pressure switch 60 shifts from a state corresponding to the engaged state to a state corresponding to the released state from the state corresponding to the engaged state to the state corresponding to the released state. The pressure switch 60 is in a state corresponding to the engaged state when the hydraulic oil pressure is set to be larger than the threshold value β and the hydraulic oil pressure is equal to or higher than the pressure threshold value α, and the hydraulic oil pressure is equivalent to the pressure threshold value β. In the following cases, the pressure switch 60 is in a state corresponding to the released state. Thus, by focusing on the two threshold values of the pressure switch 60 having hysteresis, the state of the pressure switch 60 can be suitably estimated based on the pressure command value.

  (6) The pressure threshold β is set to a value lower than the lowest value at which a force for engaging the friction element is generated. Thereby, two different states of the pressure switch 60 can be appropriately associated with two different states of the friction element.

(Other embodiments)
The above embodiment may be modified as follows.

  In the above-described embodiment, during the gear ratio switching control, the abnormality diagnosis is permitted and prohibited for each of the engagement-side friction element and the disengagement-side friction element. However, the present invention is not limited to this. For example, the abnormality diagnosis process may be prohibited until the timing at which it is assumed that the state of the pressure switch 60 corresponds to the state of the friction element after switching for all the friction elements whose engagement state is switched during the gear ratio switching control. Such a setting is particularly suitable when diagnosing the presence or absence of abnormality based on the engagement state pattern of a plurality of friction elements.

  -The parameter used in estimating the actual pressure based on the hydraulic oil command value is not limited to the hydraulic oil temperature. For example, the outside air temperature and the coolant temperature of the engine 10 may be used. Here, since the temperature of the cooling water of the engine 10 has a correlation with the operating time of the engine 10 and the automatic transmission, it has a correlation with the increase of the temperature of the hydraulic oil, and the outside air temperature is an initial condition of the temperature of the hydraulic oil. And have a correlation. For this reason, these parameters can be used instead of the temperature of the hydraulic oil.

  The structure of the transmission gear mechanism 20, the structure of the automatic transmission control circuit 44, and the structure of the pressure switch 60 are not limited to those illustrated in the above embodiment. In short, as an automatic transmission device, a friction element that is used for switching a plurality of power transmission paths and that is switched between an engaged state and a released state by a working fluid, and the operation that acts on the friction element. Any pressure response member may be used as long as the pressure of the fluid is different from the value when the friction element is brought into the engaged state and the value when the friction element is brought into the released state.

The figure which shows the whole structure of the automatic transmission control system of one Embodiment. The figure which shows the structure of the automatic transmission control circuit in the embodiment. Sectional drawing which shows typically the structure of the friction element concerning the embodiment. Sectional drawing which shows the cross-section of the pressure switch concerning the embodiment. The figure which shows the state change of the pressure switch concerning the embodiment. The figure which shows the engagement aspect of the clutch and brake in each gear stage concerning the embodiment. The time chart which shows the diagnosis permission aspect of the presence or absence of abnormality of the control at the time of gear ratio switching control concerning the embodiment. The time chart which shows the estimation method of the actual hydraulic pressure of the releasing side friction element in the embodiment. The flowchart which shows the procedure of the engagement side abnormality diagnosis permission process in the embodiment. The figure which shows the map used for estimation of the actual hydraulic pressure concerning the embodiment. The flowchart which shows the procedure of the releasing side abnormality diagnosis permission process in the embodiment. The flowchart which shows the procedure of the diagnostic process of the presence or absence of abnormality of the gear ratio switching control concerning the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Engine, 20 ... Transmission gear mechanism, 60 ... Pressure switch, 90 ... ECU (automatic transmission abnormality diagnosis device).

Claims (7)

A friction element that is used for switching a plurality of power transmission paths and that is switched between an engaged state and a released state by a working fluid, and the pressure of the working fluid that acts on the friction element engages the friction element. When the transmission ratio is controlled by the operation of the state of the friction element in an automatic transmission including a pressure response member that is in a different state between a value when the engagement state is set and a value when the release state is set, the pressure ratio In the automatic transmission abnormality diagnosis device that diagnoses the presence or absence of abnormality in the control of the gear ratio based on the state of the response member,
Estimating means for estimating a period during which the state of the pressure response member does not correspond to the operation state of the friction element according to the control of the transmission ratio based on a command value of the pressure of the working fluid;
A prohibiting means for prohibiting the determination that there is an abnormality in the control in a period not corresponding to the control,
The pressure response member changes from a state corresponding to the disengaged state to a state corresponding to the disengaged state from a state corresponding to the first state where the first pressure threshold value is shifted from the state corresponding to the disengaged state to the state corresponding to the engaged state. It is set to be larger than the second pressure threshold at the time of transition,
In the engagement state, after the command value of the pressure of the working fluid is once increased to a value larger than the first pressure threshold value, a quick filling process is performed to lower the first pressure threshold value, After the rapid filling process, a process of gradually increasing the command value is performed,
In the estimation, the estimating means assumes that the pressure response member is in a state corresponding to the engaged state when the pressure of the working fluid is equal to or higher than the first pressure threshold, and the pressure of the working fluid. Is equal to or less than the second pressure threshold value, the pressure response member is in a state corresponding to the released state, and does not correspond to the command value when the gradually increasing process is performed. An abnormality diagnosis device for an automatic transmission, characterized in that the end of a period is estimated .   The estimation means is based on a command value of the pressure of the working fluid that acts on the friction element when the friction element changes from one of the released state and the engaged state to the other in accordance with the change in the gear ratio. The abnormality diagnosis device for an automatic transmission according to claim 1, wherein a period during which the state of the pressure response member shifts to a state corresponding to the other state is estimated.   3. The automatic according to claim 1, wherein the estimation means takes into account a response delay time of an actual pressure of the working fluid with respect to a change in the command value when estimating the period based on the command value. Transmission abnormality diagnosis device. The estimating means, the response delay time, the abnormality diagnosis device for an automatic transmission according to claim 3, wherein the clear picture by the temperature of the working fluid.   Judgment means for judging that the control is abnormal based on the fact that the state of the pressure response member and the operation state of the friction element do not continuously correspond for a predetermined period or longer in the release state of the judgment prohibition by the prohibition means. The abnormality diagnosis device for an automatic transmission according to any one of claims 1 to 4, further comprising: The abnormality in the automatic transmission according to any one of claims 1 to 5, wherein the second pressure threshold is set to a value lower than a minimum value at which a force for engaging the friction element is generated. Diagnostic device. An abnormality diagnosis device for an automatic transmission according to any one of claims 1 to 6 ,
An automatic transmission control system comprising the automatic transmission.

Images